I think I started on Fox Hills on the army land near Aldershot in a borrowed Volvo 122, then a borrowed Mini Cooper, both shared with the owner. As I had a Daimler SP250 I also used that a bit later, it being surprisingly good unless ground clearance mattered - not much power at low speeds, but enough and delivered smoothly and controllably so it could wind its way up gravel tracks very well. Liquid mud, on the other hand!As I did Allan, Mini Cooper and Escort G.T., but Imps and Vee Dubs were usually the best production cars to use.
Another works drive could have been in a Simca Mille on the same event as the Volvo but we thought four of us driving both cars was too much. The Simca did rather well, as you would expect but so did the Volvo. As you say, the Imp, when it appeared, was pretty competitive.